Lens Help...rule of thumb

[Diviniti]

Greetings...

I'm still pretty new to the world of digital SLR cameras, so I have a question: What's the rule of thumb regarding mm and zoom capabilities? The bigger the number of mm the closer the zoom? Or vice versa?

Also, I have an Olympus E410 and have noticed that some of the Zuiko lenses for it have an ED and some don't. For example ZUIKO DIGITAL 11-22mm F2.8-3.5 lens and a ZUIKO DIGITAL ED 70-300mm F4.0-5.6 lens. What does the ED mean, exactly?

Thank you

 

[JimmyO]

Yup , you got it correct. And the smaller the "f/" the wider the aperture opens which makes for a lens that can shoot in less light and make for a smaller depth of focus.

 

[Socrates]

Greetings...

I'm still pretty new to the world of digital SLR cameras, so I have a question: What's the rule of thumb regarding mm and zoom capabilities? The bigger the number of mm the closer the zoom? Or vice versa?

Thank you

The rule was determined for 35mm cameras. A normal human being can hold a camera sufficiently steady if the shutter speed is 1/[focal_length] or faster (briefer). In the case of digital SLRs for the consumer market, the sensor frame is smaller than the 35mm frame, which affects the Field of View. Bottom line is to multiply the focal length by 1.5 before applying the rule.

Vibration Reduction in the lens or camera does, of course, change everything.

The rule does NOT apply at all if your camera allows you to view the LCD screen. It's not reasonable to be able to hold a camera at arms' length as steady as you would when holding it against your eye.